Dynamics & Space Flashcards
How is the distance travelled by an object measured?
The distance travelled is measured along the path followed by the object
How do you measure the displacement of an object?
The displacement is measured in a Straight Line from it’s start point to it’s finish point
What is a scalar quantity?
A Scalar has size only. e.g Distance,Speed ,Mas,energy, density
What is a vector quantity?
A vector has size and direction. e.g Displacement,Velocity, weight, acceleration , force
What is the relationship between Distance,speed and time?
D= s x t
D= distance
s= speed
t=time
What is the relationship between Displacement and velocity?
D = V x t D = displacement v= velocity t= time
How are vectors in a straight line added?
Using Normal Arithmetic
what are the two ways to add vectors at a right angle?
By scale drawing or by calculation using pythagoras
How are vectors added in a scale drawing?
Nose to Tail
what do you use to find the bearing of a vector?
SoH CaH ToA
how do you measure a bearing?
In a circle from North.
How do you write a bearing?
21 degrees = 021
210 degrees = 210
What three things of an object can forces change?
Shape
Speed
Direction
What is weight?
Weight is the gravitational force acting on an object.
Can weight change?
Yes. The weight of an object can and does change as it moves.
What is the relationship between mass,weight and gravitational field strength?
W=mg
W= weight
m= mass
g= gravitational field strength
What is the relationship between gravitational field strength and acceleration due to gravity? (when frictional forces are ignored)
Gravitational field strength is numerically equal to acceleration due to gravity when frictional forces can be ignored.
What is Friction?
Friction is a force that opposes motion
When do we wish to increase the frictional force of two objects?
When a car is going round a corner,the force of friction between the tyres and the road helps to keep the car on the road
When do we wish to decrease the frictional force acting on two objects?
skier in a downhill race wants to get to the finish line as quickly as possible.
What is newtons First law of motion?
An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
What is Newton’s Second Law?
When an unbalanced force acts on an object,the acceleration is directly proportional to the unbalanced force and inversely proportional to the mass of the object.
What is the relationship between resultant force,mass and acceleration?
F=ma
F=resultant force
m=mass
a=acceleration
What is Newton’s third law?
Every force causes and equal and opposite force.
Action-Reaction forces occur between two different objects.Each force acts on one of the objects
What is the law of conservation of energy?
Energy cannot be created and it cannot be destroyed
What is the relationship between work,force and distance?
Ew=Fd
Ew=Work
F=Force
d=distance
When is 1 joule of work done?
1 joule of work is done when a force of 1N moves through a distance of 1m
What is power?
Power is the rate at which work is done or the rate at which energy is converted from one form to another
What is the relationship between power,work and time?
P=Ew/t
P = power
Ew = Work
t= time
What is 1 watt equal to?
1 joule per second (Js^-1)
How is Gravitational potential energy gained or lost?
Moving the object vertically
What is kinetic energy?
Kinetic energy is energy that an object has because of it’s mass and it’s motion
How do you calculate efficiency of a machine?
Percentage efficiency = useful Eo/Ei x 100
Eo = Energy Output
Ei= Energy Input
What are projectiles?
Projectiles are objects that are moving in an area of space where there is gravitational force.
What is terminal velocity?
is when an object falls far enough,the air resistance becomes equal to the weight of the object. The object then moves with a constant downward velocity.
When an object is projected horizontally how does the Horizontal and vertical motion affect each other?
The horizontal motion does not effect the vertical motion and it’s vertical motion has no effect on it’s horizontal motion.
Describe a satellite’s speed in orbit.
A satellite has a large,constant horizontal speed that is changing direction all the time. These satellites are “Constantly falling” without getting closer to the object they orbit.
What is the speed of light?
3x10^8 ms^-1
How do you calculate a light year?
Speed of light x (60x60x24x365.25) - seconds in one year-
What is light year a measure of?
distance
Where is space generally accepted as beginning?
100km above the surface of the earth
What are some challenges of space Exploration?
The energy required to send a space shuttle into space makes it difficult and expensive
There is no atmosphere in space and astronauts spaceships and suits must protect them.
Space is very cold and there can be great temperature changes in Space. Spaceships and suits must be highly insulated.
manoeuvring a spacecraft in zero friction environment
maintaining enough energy to operate life support
travelling long distances using Ion drive
What are some risks of Space exploration?
Fuel load on take off potential exposure to radiation and Solar flares pressure differential re-entry through an atmosphere Micrometeorites Space Debris
What are some benefits of Space Exploration?
Insulation materials and Fire-resistant materials
Infrared aural thermometers
Powdered lubricants
anti-icing systems for aircraft
What is the difference between a challenge and a risk?
Risks concern risks to human life
Challenges are something that is blocking you but is overcomable
What is cosmology?
Cosmology is the study of the origins and development of the universe
What is the approximate estimated age of the universe?
13.8 Billion years old
How are radio telescopes used to detect astronomical objects?
Generally large parabolic dishes.
Detect energy from SuperNovae, pulsars and Interstellar gas
How are Infrared telescopes used to detect astronomical objects?
Need to be cooled and shielded from warm objects
Used to detect energy from “colder” objects such as dust and the cores of galaxies
How are X-Ray and Gamma ray telescopes used to detect astronomical objects?
Used to detect high energy photons
mainly space based or high altitude telescopes.
Objects like binary stars, pulsars and Supernovae emit radiation in these wavelengths
